North Korea is acutely embarrassed by defectors, who flee into China, Russia or, in rarer cases, into South Korea.
Crossing into South Korea is particularly treacherous as the border is marked by trigger-happy soldiers on both sides.
Those on the North Korean side are instructed to shoot anyone attempting to cross from South Korea – as well as anyone attempting to flee in the opposite direction.
On Monday a North Korean soldier successfully defected, suffering injuries after his fellow soldiers opened fire on him as he made his move.
South Korea said the soldier was shot and wounded by North Korean military during the daring escape across the DMZ.
The soldier was found on the south side of the border village of Panmunjom, about 50 metres south of the Military Demarcation Line.
He was wounded in his shoulder and elbow, according to a defence ministry official, but finally rescued in a tense operation by South Korean soldiers.
The soldier had been stationed at a guard post before leaving his position and dashing across the border.
One ministry official said: “The defector was urgently transferred to hospital in a helicopter of the United Nations Command, and there was no exchange of fire with our side.
“Since it was an area exposed to the North, we had to crawl toward there to get him out.”
The South Korean ministry official said the soldier’s condition and military rank remained to be verified.
While on average more than 1,000 North Koreans defect to South Korea every year, most travel via China and it is unusual for a North Korean to cross the land border with South Korea.
The last such crossing was in June. Defections into China across the Tumen River are far more common. Even within China defectors face danger at every step, with Beijing aiding Pyongyang by forcibly returning captured defectors.
Defectors must successfully travel thousands of miles across China into south-east Asia, where they travel through Vietnam, Laos or Thailand.
From there they can seek sanctuary and organise a flight to South Korea, where defectors are given assistance and prepared for life outside the hermit state.
The defection comes at a time of increased tension on the Korean peninsula, with fears of another highly-provocative missile launch growing.